The Reliability of Commonly Used Radiographic Parameters in the Evaluation of the Pre-Arthritic Hip

Validation of AI-driven measurements for hip morphology assessment

RATIONALE AND OBJECTIVES

Accurate assessment of hip morphology is crucial for the diagnosis and management of hip pathologies. Traditional manual measurements are prone to mistakes and inter- and intra-reader variability. Artificial intelligence (AI) could mitigate such issues by providing accurate and reproducible measurements. The aim of this study was to compare the performance of BoneMetrics (Gleamer, Paris, France) in measuring pelvic and hip parameters on anteroposterior (AP) and false profile radiographs to expert manual measurements.

MATERIALS AND METHODS

This retrospective study included AP and false profile pelvic radiographs collected from private practices in France. Pelvic and hip measurements included the femoral neck shaft angle, lateral center edge angle, acetabular roof angle, pelvic obliquity, and vertical center anterior angle. AI measurements were compared to a ground truth established by two expert radiologists. Performance metrics included mean absolute error (MAE), Bland-Altman analysis, and intraclass correlation coefficients (ICC).

RESULTS

AI measurements were performed on AP views from 88 patients and on false profile views from 60 patients. They demonstrated high accuracy, with MAE values inferior to 0.5 mm for pelvic obliquity and inferior to 4.2° for all pelvic angles on both views. ICC values indicated good to excellent agreement between AI measurements and the ground truth (0.78-0.99). Notably, no significant differences were found in AI measurement accuracy between patients with normal and abnormal acetabular coverage.

CONCLUSION

The application of AI in measuring pelvic and hip parameters on AP and false profile radiographs demonstrates promising outcomes. The results reveal that these AI-powered measurements provide accurate estimations and show strong agreement with expert manual measurements. Ultimately, the use of AI has the potential to enhance the reproducibility of measurements as part of comprehensive hip assessments, thereby improving diagnostic accuracy.

Borderline Hip Dysplasia - Best Treated with Hip Arthroscopy or Periacetabular Osteotomy?

PURPOSE OF REVIEW

As the field of hip preservation evolves, the diagnosis of borderline dysplasia (defined as a lateral center edge angle between 18°-25°) has shown itself to be one of the more challenging diagnoses to treat. As the nuances of acetabular coverage have come to light, the question of whether borderline hip dysplasia is best treated with isolated hip arthroscopy, periacetabular osteotomy, or whether a combined procedure is best, is now top of mind. The goal of these procedures is to not only improve patient symptoms, but to correct underlying pathology and ideally slow the development of hip osteoarthritis. The purpose of this review is to summarize the recent literature and clinical findings regarding both isolated hip arthroscopy and periacetabular osteotomy in the surgical management of borderline hip dysplasia.

RECENT FINDINGS

Current research demonstrates improved postoperative clinical outcome scores for both patients who had isolated hip arthroscopy in the setting of borderline hip dysplasia and for those patients who underwent periacetabular osteotomy. Mid-term outcomes for patients in both groups have showed low rates of conversion to total hip arthroplasty. No gold standard in the surgical management of borderline hip arthroscopy exists. Improved clinical outcomes have been seen postoperatively in patients who undergo hip arthroscopy and in patients who undergo periacetabular osteotomy. Successful clinical outcomes seem to rely on treatment of the underlying clinical pathology and are largely based on the appropriate surgical indications and appropriate surgical techniques. Surgical decision making in this patient population should be individualized based on a comprehensive evaluation of the patient.

A pilot screening project for the detection of hip dysplasia in young patients

Hip dysplasia in young adults is underdiagnosed and can cause pain and discomfort. Progression to osteoarthritis (OA) is common, necessitating total hip arthroplasty at an early age. When discovered early, symptomatic patients can be offered physiotherapy and/or hip-preserving surgery to alleviate pain and decrease the risk of early OA. A pilot project to screen radiograms for hip dysplasia was started across the Swedish region of Örebro Län in January 2019, comparing the incidence of dysplasia before and after initiation of the screening program. All elective conventional radiograms of the hip (age 12-44 years), requested by primary care physicians, were analyzed by consultant radiologists according to a pre-established algorithm to identify hip abnormalities. If the hip radiograms showed dysplastic changes, or other pathological signs, the radiologist advised referral to a specialized Youth Hip Clinic for further work-up and treatment. A total of 1056 radiograms were requested by clinicians during the study periods (601 and 455 during 2018 and 2020, respectively). A total of 457 trauma-related cases were excluded, resulting in 599 available for analysis (348 and 251 during 2018 and 2020, respectively). During 2018, 17 patients (4.9%) received the radiologic diagnosis of dysplasia, compared with 44 patients (17.5%) during 2020 (P < 0. 001). A three-fold increase of patients diagnosed with hip dysplasia was detected as a result of the implementation of the screening program. The advantage of screening is early referral to an orthopedic department for evaluation and consideration for physiotherapy and/or surgical intervention.

Femoroacetabular Impingement Measurements Obtained From Two-Dimensional Radiographs Versus Three-Dimensional-Reconstructed Computed Tomography Images Result in Different Values

Purpose

To compare the reliability and accuracy of radiographic measurements obtained from 2-dimensional (2D) radiographs and 3-dimensional (3D)-reconstructed computed tomography (CT) images in the assessment of femoroacetabular impingement syndrome (FAIS).

Methods

Consecutive patients with FAIS from January 2018 to December 2020 were identified and included in this study. Two fellowship-trained surgeons and 2 fellows performed blinded radiographic measurements. Lateral center-edge angle (LCEA) and Tönnis angles were measured on anteroposterior pelvic radiographs, and alpha angles were measured on frog lateral radiographs. Reliability coefficients for individual measurement accuracy were performed using the Cronbach alpha and intra- and inter-rater intraclass correlation coefficients (ICCs). Composite measurements for LCEA, Tönnis angle, and alpha angle were compared with the corresponding 3D value using paired sample t-tests.

Results

Fifty-three patients with FAIS with standardized 2D radiographic and 3D-reconstructed CT imaging were included. All reliability metrics met thresholds for internal reliability. Inter-rater ICCs for LCEA, Tönnis angle, and alpha angle were (0.928, 0.888, 0.857, all P < .001). When we compared 2D radiographic measurements with 3D-reconstructed CT values, there was a significant difference in the LCEA for 2 authors: surgeon 1 (mean [M] = -9.14, standard deviation [SD] = 5.7); t(52) = -11.6, P < .001, and surgeon 2 (M = -5.9°, SD = 4.7); t(52) = -9.2, P < .001. Significant differences were seen for Tönnis angle for 2 authors: fellow 2 (M = 3.9°, SD = 5.6); t(52) = 5.1, P < .001, and surgeon 2 (M = -2.6°, SD = 4.1); t(52) = -4.6, P < .001. Alpha angle measurements compared to the 3D-reconstructed alpha angle at 2 o'clock was significantly different for 3 authors: fellow 1 (M = 11.9°, SD = 16.2); t(52) = 5.3, P < .001; fellow 2 (M = 10.4°, SD = 18.6); t(52) = 4.1, P = .002; and surgeon 2 (M = -6.5°, SD = 16.2); t(52) = -2.9, P = .005. Positive mean values indicate 2D radiographic measurements overestimated 3D reconstruction values and negative mean values indicate underestimation.

Conclusions

The use of 2D radiographs alone for preoperative planning of FAIS may lead to inaccuracies in radiographic measurements.

Level of Evidence

Level, III retrospective cohort study.

Radiographic parameters of pelvic and proximal femoral morphology do not predict outcomes for direct anterior total hip arthroplasty

BACKGROUND

Radiographic predictors of outcomes associated with direct anterior approach (DAA) total hip arthroplasty (THA) are largely unknown. Anecdotally, some surgeons limit surgery to patients with low body mass index (BMI) or "favorable" bony morphology. Objective data on the impact of these factors is limited. We sought to determine radiographic and demographic predictors of outcomes after DAA arthroplasty.

METHODS

A consecutive series of patients undergoing unilateral, elective DAA THA, who had linked pre- and post-operative patient reported outcome scores, from January 1, 2017 to March 30, 2019 were included. Radiographic measurements, including proxies for pelvic overhang, femoral canal access, acetabular morphologic changes, and markers of disease severity, were performed on calibrated radiographs. Intra-observer consistency was also evaluated. Outcome measures included disease specific and general health patient-reported outcomes scores, while surgical difficulty was approximated by estimated blood loss and surgical time. Multivariate analyses were performed to determine statistically significant correlations.

RESULTS

168 patients were included. Overall, patients experienced significant improvement in outcome scores (mean ∆ HOOS-JR 39.4, PROMIS-physical 12.3). There were two reoperations (1.2%), for recurrent dislocation. Female sex (p = 0.015) and increasing age (p == 0.019) were associated with shorter surgical times. No statistically significant correlations were found between the radiographic parameters and outcome measures. Intraclass correlation coefficients of the radiographic measurements were overall strong (0.73-1.0).

CONCLUSION

We demonstrated consistent results in this series of patients despite variation in bony morphology. Our findings suggest that DAA THA can be safely performed on a broader patient population.

Anterior and Lateral Femoroacetabular Excursion Angles Are Helpful for Assessing Femoroacetabular Impingement Syndrome: A Cross-Sectional Cohort Study

PURPOSE

To develop a radiographic measurement to evaluate the femoroacetabular space using 3-dimensional (3D) hip models in asymptomatic hips, and to evaluate the reliability and validity of the femoroacetabular excursion angle (FAEA) in symptomatic patients.

METHODS

From January 2020 to December 2020, we recruited patients with healthy hips to establish 3D models. Through the simulation of 14 activities of daily living (ADLs), anterior and lateral impingement-free FAEAs were measured. Another cross-sectional cohort was formed from consecutive symptomatic subjects with impingement signs during the same period. In the validation cohort, anterior and lateral FAEAs were assessed on modified Dunn's and anteroposterior views of the hip, respectively. We evaluated the reliability and clinical implications of the FAEAs.

RESULTS

In the discovery cohort (n = 33), hips with collisions tended to have smaller computed tomography-based FAEAs than collision-free hips, although alpha and lateral center-edge (CE) angles were comparable. Additionally, hips with a lower quartile of FAEAs had a significantly higher number of ADLs with collisions. In the validation cohort (n = 411), the FAEA measurement was highly reliable (kappa statistics >0.95 for both interobserver and intraobserver reliabilities). The femoroacetabular impingement syndrome (FAIS) group (n = 165) showed significantly smaller anterior and lateral FAEAs than the non-FAIS group (all P < .001, Cramer V = .420). The optimal cut-off values for anterior and lateral FAEAs were 32.6° and 48.9°, respectively. In univariate regression, anterior (odds ratio [OR] = 0.91; 95% confidence interval [CI] = 0.89-0.94) and lateral (OR = 0.91; 95% CI = 0.89-0.93) FAEAs were significantly associated with FAIS. Moreover, in multivariate regression adjusted for alpha and lateral CE angles, anterior FAEA remained a significant predictor (OR = 0.96; 95% CI = 0.93-0.99), and small FAEA was an independent risk factor for FAIS (OR = 1.99; 95% CI = 1.06-3.71) for any small FAEA (OR = 2.88; 95% CI = 1.32-6.31) for both small FAEAs.

CONCLUSION

The FAEA is a valid measurement for FAIS with high reliability. Small FAEA was an independent risk factor for FAIS in the multivariate regression model, even after adjusting for alpha and lateral CE angles.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Standard radiographic values for the acetabulum in Japanese adolescents: a cross-sectional study

BACKGROUND

Most previous reports of normal acetabular radiographic values focused on adults or elderly people. Recent reports have described premature hip osteoarthritis in adolescents not caused by acetabular dysplasia. In addition, there is a certain failure rate of surgical treatment for young patients with borderline acetabular dysplasia. Accurate indices for treatment of adolescent hips are unclear because standard measurement values of the adolescent acetabulum have not been reported.

METHODS

This cross-sectional study involved 552 Japanese adolescents aged 12-18 years who had scoliosis or suspected scoliosis and asymptomatic hips. All persons underwent plain standing anteroposterior whole-spine radiography, and measurements were obtained using the pelvic part of the radiograph. We excluded persons who were unable to correctly perform measurements because of conditions such as pelvic rotation or lateral inclination and persons in whom closure of the triradiate cartilage or closure of the secondary ossification centers of the acetabulum had not yet occurred. In 1101 hips, we measured the lateral center-edge angle (LCEA), Tönnis angle, Sharp angle, acetabular head index (AHI), lateral subluxation (LS), vertical subluxation (VS), and peak-to-edge distance (PED). We evaluated the correlation coefficient and coefficient of determination between each parameter and age, height, body weight, and body mass index (BMI) and assessed the intra- and inter-rater reliability of each radiographic parameter.

RESULTS

Among all hips, the mean of each parameter was as follows: LCEA, 27.9° ± 4.8°; Tönnis angle, 5.0° ± 3.7°; Sharp angle, 44.1° ± 3.1°; AHI, 82.1% ± 5.5%; LS, 5.4 ± 1.4 mm; VS, 0.3 ± 1.2 mm; and PED, 14.0 ± 2.3 mm. The correlation between each parameter and age, height, body weight, and BMI was considerably low. Intra- and inter-rater reliability was moderate or good for almost all parameters.

CONCLUSIONS

The values for each radiographic parameter of the acetabulum in this study are considered standard for the adolescent acetabulum without age-related changes. Some parameters differ slightly from the normal values for adults or elderly people in previous reports; thus, we suggest careful evaluation of these parameters for adolescents.

Reliability of the Garden Alignment Index and Valgus Tilt Measurement for Nondisplaced Femoral Neck Fractures

Anteroposterior (AP) alignment assessment for nondisplaced femoral neck fractures is important for determining the treatment strategy and predicting postoperative outcomes. AP alignment is generally measured using the Garden alignment index (GAI). However, its reliability remains unknown. We compared the reliability of GAI and a new AP alignment measurement (valgus tilt measurement [VTM]) using preoperative AP radiographs of nondisplaced femoral neck fractures. The study was designed as an intra- and inter-rater reliability analysis. The raters were four trauma surgeons who assessed 50 images twice. The main outcome was the intraclass correlation coefficient (ICC). To calculate intra- and inter-rater reliability, we used a mixed-effects model considering rater, patient, and time. The overall ICC (95% CI) of GAI and VTM for intra-rater reliability was 0.92 (0.89−0.94) and 0.86 (0.82−0.89), respectively. The overall ICC of GAI and VTM for inter-rater reliability was 0.92 (0.89−0.95), and 0.85 (0.81−0.88), respectively. The intra- and inter-rater reliability of GAI was higher in patients aged <80 years than in patients aged ≥80 years. Our results showed that GAI is a more reliable measurement method than VTM, although both are reliable. Variations in patient age should be considered in GAI measurements.

Femoroacetabular translation in female athletes and dancers assessed by dynamic hip ultrasonography

Objective

To compare femoroacetabular (FA) translation between dancers and athletes with hip pain and between dancers with and without hip pain.

Methods

In this cross-sectional study, 171 female athletes and dancers with hip pain underwent dynamic hip ultrasound (DHUS) of FA translation in three positions: neutral (N), neutral with contralateral hip flexion (NF), apprehension position with contralateral hip flexion (EER-F). Multivariable linear regression analysis was used to assess variation in FA translation between dancers and athletes in the presence of age, Beighton score/hypermobility, BMI, radiographic markers of acetabular dysplasia and femoral version angles. Symptomatic dancers were matched to asymptomatic dancer controls on age, height and BMI, and comparison analyses of FA translation were conducted controlling for matched propensity score and Beighton score.

Results

In the symptomatic cohort, dancers were younger, had higher Beighton scores and were more hypermobile than non-dancers. Dancers also showed greater NF, EER-F and max US–min US (delta) compared with non-dancers (mean 5.4 mm vs 4.4 mm, p=0.02; mean 6.3 mm vs 5.2 mm, p=0.01; 4.2 mm vs 3.6 mm, p=0.03, respectively). Symptomatic dancers showed greater NF and EER-F compared with asymptomatic dancers (mean 5.5 mm vs 2.9 mm, p<0.001; mean 6.3 mm vs 4.2 mm, p<0.001, respectively). Comparison of symptomatic dancers with and without hip dysplasia showed no difference in DHUS measurements.

Conclusion

DHUS measurements of FA translation are greater in female dancers with hip pain relative to female non-dancer athletes with hip pain and asymptomatic female dancers.

Activity Level and Sport Type in Adolescents Correlate with the Development of Cam Morphology

The purpose of this study was to evaluate the influence of the volume and type of sport on the development of cam-type femoroacetabular impingement and acetabular dysplasia.

There is no definite consensus on the adequate radiographic correction in arthroscopic osteochondroplasty for femoroacetabular impingement: a systematic review and meta-analysis

PURPOSE

The purpose of this study is to evaluate and define what is considered an adequate radiographic correction in arthroscopic osteochondroplasty for FAI and to secondarily assess how radiographic outcomes relate to patient reported outcomes and complications.

METHODS

The databases EMBASE, PubMed, and MEDLINE were searched for relevant literature from database inception until January 2021. Studies were screened by two reviewers independently and in duplicate for studies reporting on post-operative radiographic outcomes in arthroscopic osteochondroplasty for FAI. Data on radiographic outcomes as well as data reporting functional outcomes and complications were recorded. A meta-analysis was used to combine the mean pre- and post-operative radiographic outcomes using a random effects model. A risk of bias assessment was performed for all included studies using the MINORS score.

RESULTS

The most commonly reported radiographic outcome was the alpha angle with a pooled mean post-operative angle of 44° (95% CI 41°-46°), and mean pre- to post-surgical difference of - 19° (- 22 to - 16, I² = 96%), followed by the LCEA with a pooled mean post-operative angle of 30° (95% CI 29-31) and mean difference after surgery of - 4° (- 6 to - 1, I² = 97%,). Eleven studies reported on the correlation between radiographic and clinical outcomes with no consistent consensus correlation found amongst the included studies. Similarly, six studies correlated radiographic outcomes with conversion to THA with no consistent consensus correlation found amongst the included studies.

CONCLUSION

Based on this review, the main conclusion is that there is no consensus definition on the optimal radiographic correction for FAI and there was no consistent correlation between radiographic correction and functional outcomes. However, based on the uniform improvement in functional outcomes, this review suggests a post-operative alpha angle target of 44° with a correction target of 19° and LCEA target of 30° with a correction target of 3°.

LEVEL OF EVIDENCE

IV.

No Correlation Between Depth of Acetabuloplasty or Postoperative Lateral Center-Edge Angle on Midterm Outcomes of Hip Arthroscopy With Acetabuloplasty and Labral Repair

BACKGROUND

The treatment of pincer deformity in hip arthroscopy remains controversial, with some authors advocating that over resection may risk early joint deterioration. The role of acetabular resection depth and postoperative acetabular morphology on postoperative outcomes has yet to be defined.

PURPOSE/HYPOTHESIS

This study measures the influence of acetabular resection depth and postoperative lateral center-edge angle (LCEA) on minimum 5-year patient-reported outcomes (PROs), revision rates, and conversion to total hip arthroplasty using a single surgeon's prospective database. We hypothesized that patients with acetabular resections >10°, as measured by LCEA, or patients with postoperative LCEA outside the normal range of 25° to 35° would have lower PROs, higher revision rates, and higher conversion to total hip arthroplasty at midterm follow-up.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A total of 192 patients who underwent primary hip arthroscopy with acetabuloplasty and labral repair by a single surgeon with a minimum 5-year follow-up met the inclusion criteria. Preoperative and postoperative LCEAs were measured on supine anteroposterior radiographs, and patients were divided into cohorts based on LCEA and acetabular resection depth. Cohorts for postoperative LCEA were <20° (dysplasia), 20° to 25° (borderline dysplasia), 25° to 35° (normal), and >35° (borderline overcoverage). Cohorts for acetabular resection depth were <5°, 5° to 10°, and >10° difference from preoperative to postoperative LCEA. Outcome measures included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), 12-Item Short Form Health Survey, modified Harris Hip Score, Hip Outcome Score, satisfaction scores, revision rates, and conversion to arthroplasty rates.

RESULTS

Patients significantly improved in all outcome score measures at final follow-up. There were no statistically significant differences in PRO scores or conversion to total hip arthroplasty between any cohorts in the postoperative LCEA group. There were more revisions in the 25° to 35° cohort than the other cohorts (P = .02). The 5-10° resection depth cohort demonstrated a higher postoperative WOMAC score (P = .03), but otherwise no statistically significant differences were seen between resection depth cohorts in the remaining postoperative outcomes scores, revision rates, or conversion to total hip arthroplasty rates.

CONCLUSION

Patients with postoperative LCEA values outside the normal reference range and with large resections perform similar to those with normal postoperative LCEA values and smaller resections at a minimum 5-year follow-up.

Developmental Dysplasia of the Hip in Adolescents and Young Adults

Developmental dysplasia of the hip (DDH) in adolescents and young adults can cause notable pain and dysfunction and is a leading cause of progressive hip osteoarthritis in affected patients. Recognition of the clinical symptoms and radiographic presentation of DDH in adolescents and young adults are paramount for early management. Plain radiographs are critical for making proper diagnosis, whereas three-dimensional imaging including MRI and/or CT detects intra-articular pathology and better characterizes hip morphology. Management of early, symptomatic DDH includes nonsurgical modalities and open joint preservation techniques. Arthroscopic management can be used as an adjunct for symptomatic treatment and for addressing intra-articular pathology, but it alone does not correct the underlying osseous dysplasia and associated instability. The periacetabular osteotomy has become the mainstay of efforts to redirect the acetabulum and preserve the articular integrity of the hip; however, the proximal femur is also a potential source of pathology that should be considered. Open hip procedures are technically demanding yet provide the opportunity for pain relief, improved function, and preservation of the hip joint.